S-Max is a large volume sand casting 3D printer by ExOne used to additively manufacture molds needed for industrial metal casting. This machine does not print directly in metal but makes casts and cores to pour in molten metal by jet binding fine powder. It works similary to your desktop inkjet paper printer but it applies special Furan resin binder to layers of silica sand, cerabeads or zirconia which are “glued” together making a solid 3D cast.
Since there is no heat transfer issues, laser or electron beam focusing or direct welding of metal, molds produced can be very precise and with intricate details. There is no complex dynamics of melting metal together and material heating-cooling stress so the parts can be very large. Using fine sand powder and binder reduces the need for postprocessing and the casts are ready almost instantly after 3D printing with minimal cleaning needed.
S-Max technical specifications:
- Process cell includes job box and roller conveyor
- Build volume l x w x h: 1800 x 1000 x 700 mm, (70.9 x 39.37 x 27.56 in.)
- Build speed: 60,000 to 85,000 cm3/h (2.12 to 3.00 ft3/h)
- Layer thickness: 0.28 to 0.50 mm (0.011 to 0.0197 in.)
- Print resolution: X/Y 0.1 mm / 0.1 mm (0.004 in. / 0.004 in.)
- External dimensions including one job box, right – standard l x w x h: 6900 x 3520 x 2860 mm, (271.7 x 138.6 x 112.6 in.)
- Weight: 6500 kg (14,330 lbs)
- Electrical requirements S-Max: 400V 3-Phase/N/PE / 50-60 Hz, max. 6.3 kW
- Electrical requirements heater: 400V 3-Phase/PE / 50-60 Hz, max. 10.5kW
- Data interface: STL
Here is the animated overview of the entire process:
.. and here is the process in more realistic conditions:
This powerful industrial machine comes with a hefty price tag of some 1.400.000 USD but it is important to keep in mind that this technology is not experimental but well matured and implemented 3D printing process used on industrial scale in heavy metal production for very demanding products.
The example from engineering.com shows true power of this additive manufacturing system:
For over 80 years Standard Alloys has been in the business of making high-quality castings and machined parts. When a customer approached them with the idea of casting a 57-inch impeller in short order, Standard knew they needed a new solution to meet their lead time requirements.The team at Standard were able to design and print the largest rapid casting core they had every created within 8 weeks. In fact, ExOne’s machines were capable of building the entire impeller’s core, complete with hydraulic balancing, in a single week.
Here you can see it in Hoosier Pattern Inc. industrial environment:
3D printed sand casting provides many benefits in metal 3D printing heavy industry but the question remains will this process survive in the long run with rapid advancement in other fields. Why use casting if you have affordable and large volume 3D printer based on EBF3, DMLS, EBM, SLM or SLS? There are even large industrial 3DPI machines being developed based on ultrasonic welding of metal sheets! My guestimate is that sand casting will always have some sort of cost advantage over more “high-tech” systems since it is very sturdy and can be integrated in low tech environments where there is a knowledge base of working with molten metal and there will be no need to train personnel on fine electron beam mechanics or laser optics.
You can learn more about S-Max at: